Corrosion inhibited multi-purpose metal cleaner

ABSTRACT

A MULTI-PURPOSE CLEANER COMPRISING SOLIUM METASILICATE, DODECYL BENZENE SODIUM SULFONATE, AND A NONIONIC SUFACTANT IN COMBINATION WITH A METAL CORROSION INHIBITOR CONSISTING OF SODIUM OR POTASSIUM STANNATE.

United States Patent O 3,645,905 CORROSION INHIBITED MULTI-PURPOSE METAL CLEANER Myer Rosenfeld, Baltimore, and Troy R. Nichols, Bel Air, Md., assignors to the United States of America as represented by the Secretary of the Army No Drawing. Filed Dec. 1, 1969, Ser. No. 881,305 Int. Cl. C09d 9/04; C11d 3/08; C23f 11/06 U.S. Cl. 252--540 8 Claims ABSTRACT OF THE DISCLOSURE A multi-purpose cleaner comprising sodium metasilicate, dodecyl benzene sodium sulfonate, and a nonionic surfactant in combination with a metal corrosion inhibitor consisting of sodium or potassium stannate.

The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.

This invention relates to a multi-purpose composition having utility as an alkaline metal cleaner, a paint stripper or to loosen carbon residing on the surface of pistons. More particularly, it relates to an alkaline composition having therein a small amount of sodium or potassium stannate in order to inhibit the corrosion of aluminum or alloys thereof.

Sodium or potassium chromates are usually utilized in paint removing formulations to inhibit the corrosion of the metal. However, the disopsal of waste chromates constitutes a problem in that soluble chromates are poisonous, Accordingly, many municipalities severely limit the chromium concentration permitted to enter efiluent streams or waterways. The allowable hexavalent chromium concentrate suggested by the US. Public Health Service for the protection of fish is 0.50 milligram per liter for industrial waste eflluent after mixing with receiving water. Therefore, it is often necessary to dilute the waste containing chromate to a permissible level prior to discharging into efliuent streams and waterways. When appreciable concentrations of chromates are needed for corrosion inhibition, this becomes a lengthy operation.

It is an object of this invention to provide and disclose a multi-purpose composition.

It is a further object of this invention to provide and disclose a multi-purpose composition having a corrosion inhibitor incorporated therein.

It is a further object of this invention to provide and disclose a composition comprising a corrosion inhibitor which is effective in the protection of aluminum and alloys thereof.

It is a further object of this invention to provide and disclose a composition which will obviate the need for the treatment of the cleaning solution prior to the disposition thereof into efiluent streams or waterways.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims.

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The multi-purpose composition comprises an alkaline composition consisting of sodium silicate, wherein the sodium metasilicate calculated as anhydrous comprises 57.8 to 73% sodium silicate by weight; dodecylbenzene sodium sulfonate in an amount of 17.0 to 29.8% by weight calculated on the basis of 86% active material and an nonionic surfactant comprising between 7.36 to 12.5% by weight. The nonionic surfactant may be a branched or straight chain nonylphenol containing a side chain of 15 ethylene oxide units. In the alternative, the nonionic surfactant may be a branched or straight chain octylphenol containing a side chain of 9 to 10 ethylene oxide units. In an alkaline medium of the present type, the attack on ferrous or magnesium metals is negligible, therefore, no corrosion inhibitor is essential. However, in the treatment of aluminum or alloys thereof, a corrosion inhibitor is essential to prevent corrosion of the metal. The present invention utilizes sodium and potassium stannate. Sodium stannate, calculated as anhydrous, is effective when utilized in the composition in an amount of from 0.72 to 7.5% by Weight. Potassium stannate is effective when utilized in an amount of from 0.87 to 7.5% by weight.

The present composition was evaluated in regards to its paint removing ability utilizing 28 aluminum, i.e., aluminum alloy SAE-AAllOO, panels having dimensions of 1" by 3 and a thickness of 0.034. Sharp edges were removed with 4/0-150 Alundum polishing paper. The aluminum panels were immersed for 5 minutes in an 8 ounce per gallon aqueous solution of trisodium phosphate at 180 -F., water rinsed, dipped into 50% nitric acid for a period of 30 seconds, and water rinsed. The panels were then immersed for a period of 5 minutes in an aqueous bath at room temperature containng one ounce per gallon of a composition consisting of 20% ammonium bifiuoride and chromium trioxide by weight. The panels. were then removed, water rinsed, air dried.

The multi-purpose compositions were evaluated utilizing the paint systems set forth in Table I below: The paint, which consisted of an olive-drab color, was applied by spray to one side of each panel. A coat comprising a dry film of paint having a thickness of 0.7 to 1.0 mm. was deposited on one side of each panel.

TABLE I Systems:

1 One coat alkyd enamel baked for 30 minutes at 300 R., air dried for 24 hours, then aged for 24 hours at F.

2 One coat alkyd enamel modified with 20% urea-formaldehyde, baked for 30 minutes at 300 F., air dried for 24 hours, then aged for 24 hours at 120 F.

3 One coat alkyd-red iron oxide-zinc chromate baked for 30 minutes at 300 F., cooled to room temperautre, and followed by one coat alkyd lusterless enamel baked for 30 minutes at 300 F., air dried for 24 hours, then aged for 24 hours at 120 F.

4 One coat alkyd nitrocellulose lacquer air dried for 24 hours, then aged for 24 hours at 120 F.

3 The composition was evaluated in regards to its cleana ing ability utilizing test panels of SAE-l020, 20 gage, s'jno 7 cold-worked steel having dimensions 2 /2" by 2 /2". Sharp 5 edges of the panels were smoothed and the faces polished a sage 5 m with No. 1 coarse emery cloth. The panels were then 5 t 1s 5 :1 swa'bbed with acetone, using absorbent cotton, dipped 5 into absolute alcohol and air dried. E 238 5 52.2 Two cleaning evaluations were conducted. One utilized $2 1 591 H steel panels coated with a mineral oil. The mineral oil 1 Mn tam/m utilized was Military Symbol oil 3065 conforming to 5 MIL-L-l50l6. The cleaned panel was suspended from f f a hook and dipped into a 400 ml. beaker containing about 3253 i iggw g 300 ml. of the oil at 26il C., removed and allowed 01 21 5 {AZ 3 to drain for 30 minutes. Adhering oil was approximately I 1 I 0.16 gm. a sees: a The other cleaning evaluation utilized steel panels 39 r f E" coated with asphalt. Petroleum asphalt conforming to Mama 5 f SS-A-706, grade 85-100, was used. The soil was heated i i:- j to approximately 50 C. and spread evenly over one face f i of the cleaned test panels. Between 0.32 to 0.34 gram was a gggy; 5 53am applied to each panel. grim E E 3 In addition, the compound was evaluated in regards to i i its ability to inhibit the corrosion of aluminum panels. $08? 5 7 Four panels cut from 28 aluminum sheets were utilized f E in each determination and an average figure obtained. H g f The test panels utilized measure A" by 3" and have a 32: f 5' thickness of approximately 0.03. The panels were lightly E i polished with No. 150 Alundum paper, washed with ace- 2 gag g 5 Egum tone, wiped with paper toweling, dipped into absolute 1 93 5 E ethyl alcohol and again wiped with paper toweling. After 5 Z being weighed to 0.0001 gram, the test panels were im- E E mersed in the boiling test solution for one hour. They i E E H were then removed, rinsed under flowing tap water, dipped E f into absolute ethyl alcohol and dried with paper toweling. E? E: 9} To remove any residual film that had formed during the 35 E 5 test, the panels were immersed in concentrated nitric acid ggg 2 Egm q at room temperature for a period of tWo minutes. The 11 E l panels were then rinsed thoroughly under flowing tap m E 5 water, dipped into absolute ethyl alcohol, dried with paper g to E 3 toweling and Weighed to 0.0001 gram. The difference in 40 E5 New 5 E H weight of the panels after treatment represents loss due E, E to corrosion. It was found that the average weight loss 1:: 5i :3 due to the treatment of the panels with nitric acid after E E immersion of the panels in the aqueous formulation was 5228 E Eg j around 0.05 mg. 'ooo' 5,. ts at In addition, the present composition was evaluated for D i E its ability to loosen carbon residing on the surface of m E? 5 aluminum pistons of an internal combustion engine. The E Z H pistons were immersed in a boiling aqueous solution of E i the present composition for a period of two hours. The 9 E pistons were then removed and scrubbed with a hard E bristle brush under running cold water. ggg 5 52 2 Set forth in Table II following are the results obtained 52 E from the evaluation of the present aqueous composition i E I E in regard to its alkaline cleaning, paint stripping and alu- 55 E i E E f E i E 5 minum pistons cleaning abilities. 5 i i i i f l l The steel panels which were contaminated with the E E E E E 3 i I 5 mineral oil, were cleaned by immersion in the aqueous E l l E E i g E cleaning solution for a period of 3 minutes. The panels 2 i i i E E l 1 i were then rinsed and examined for the presence of a E E i Z l i E i 5 5 water break. In Table II, the mineral oil test is designated E E i i i E 5 S for satisfactory if there is no water break apparent E i E E i f E E on the surfaces of the rinsed steel panels. E E I i i i E 3 In regards to the steel panels contaminated with the E 5% E E 5 E E :5 asphalt soil, the time required for the complete removal I, i 5E Z E f E i is: of the asphalt was noted as set forth in said Table II. A E 57;} E i i E E time of less than 13 minutes for the complete removal of i E i E 1 5.2 the asphalt soil is considered satisfactory. i E E 5 Table II discloses that the eifective amount of sodium E 5 g 3 stannate is in the range of 0.82 to 7.49 percent by weight 5 g 52, 3.: g g i g as shown in formulations 11 to 15. Potassium stannate E has utility in the range of 0.88 to 7.48 percent by weight 5 52;; g 5 5,? i as shown by formulations 1 to 8. Formulation 20 dis- 5 closes that a composition containing 35.55 percent potas- 'g'gg ggggg sium chromate by Weight therein is needed in order to g Z +E2 provide 90.91% corrosion inhibition. This compares, for 3 8 a 033 20 40 1y'2 1 /2 1 2 1 g-2 13,6-2 1 2 V Z V2- 41 2- /2' 643% /E 2-2 22} 22 99+ 99+ 99+ 99+ 1. 63 1. 05 65 35 4. 24 39. 39 63. 64 00. 00 90. 91

.38 .33 .22 .22 .22 .22 .22 .22 .22 .030 .030 .0225 .025 .37 15 -2 y 15 -2 1; 2 1&2 1

Composition, g./100 n11 example, with 0.88 percent potassium stannate required to achieve 95.15% corrosion inhibition. The amount of potassium chromate necessary to provide effective corrosion inhibition would present a disposal problem.

Although we have described our invention with a certain degree of particularity, we wish it to be understood that we do not desire to be limited to the exact details of formulations shown and described, for obvious modification will occur to a person skilled in the art.

Having described our invention, we claim:

1. A multi-pu-rpose cleaner composition consisting of 57.8 to 73 percent sodium metasilicate, 17 to 30 percent dodecylbenzene sodium sulfonate, a nonionic surfactant, in an amount of 7.36 to 12.5 percent, selected from the group consisting of nonyl phenol having a side chain of 15 ethylene oxide units and octyl phenol having a side chain of 9 to ethylene oxide units, in combination with a corrosion inhibitor selected from the group consisting of sodium stannate in an amount of 0.82 to 7.49 percent and potassium stannate in an amount of 0.87 to 7 .49 percent by weight.

2. An aqueous solution of the composition of claim 1 containing about 2.045 to about 2.580 grams of composition per 100 milliliters of solution.

3. A multi-purpose cleaner composition in accordance with claim 1 wherein the nonionic surfactant is nonyl phenol having a side chain of ethylene oxide units.

4. A multi-purpose cleaner composition in accordance with claim 1 wherein the nonionic surfactant is octyl phenol having a side chain of 9 to 10 ethylene oxide units.

5. A multi-purpose cleaner composition in accordance with claim 1 consisting of:

Ingredients: Percent by wt. Sodium metasilicate 72.97 Dodecylbenzene sodium sulfonate 18.24 Nonionic surfactant 7.88 Sodium stannate 0.91

6. A multi-purpose cleaner composition in accordance with claim 1 consisting of:

Ingredients: Percent by wt. Sodium metasilicate 72.86 Dodecylbenzene sodium sulfonate 18.22 Nonionic surfactant 8.01 Potassium stannate 0.91

7. A multi-purpose cleaner composition in accordance with claim 1 consisting of:

Ingredients: Percent by wt. Sodium metasilicate 69.78 Dodecylbenzene sodium sulfonate 17.45

Nonionic surfactant 7.54

Sodium stannate 5.23

8. A multi-pu-rpose cleaner composition in accordance with claim 1 consisting of:

OTHER REFERENCES McCutcheons Detergents and Emulsifiers, 1967, Annual, pp. 31, 155, 156 and 262.

Protective Coatings for Metals, by R. M. Burns and W. W. Bradley, 1955, pp. 156 and 165.

LEON D. ROSDOL, Primary Examiner D. L. ALBRECHT, Assistant Examiner US. Cl. X.R. 

